Method of dephosphorizing and reducing iron ore.



UNITED STATE PATENT OFFICE.

JOHN T. JONES, OF IRON MOUNTAIN, MICHIGAN, ASSIGNOR OF ONE-HALF TOGEORGE A. ST. CLAIR, OF DULUTH, MINNESOTA.

METHOD OF DEPHOSPHORIZING AND REDUCING IRON ORE.

To all whom it may concern:

Be it known that I, JOHN T. J ONES, a citizen of the United States,residing at Iron Mountain, in the county of Dickinson and State ofMichigan, have invented a new and useful Improvement in Methods ofDephosphorizing and Reducing Iron Ore, of which the following is aspecification.

My object is to provide a simple, efficient, and economical method ofpreparing and treating finely divided iron ores containing phosphoruswhich is not combined with the iron for the purpose of reducing anddephosphorizing them, preparatory to smelting, or further treatment,which will eliminate other impurities.

My improved method may be employed to advantage in the production ofsponge, clinker, or the like, from magnetite or hematite sands, orcomminuted iron ores generally wherein the phosphor content, for themost part at least, is not combined with the iron.

My invention may be practiced by first forming a cement, consisting of,say, forty parts limestone calcined with clayey matter and, say, sixtyparts of the iron ore. This cement mixture is then incorporated with amass of the iron ore in the proportion of one part of the mixture to,say, eight to sixteen parts iron ore, the final mixture being moistenedand formed into suitable briquets, which are then dried. The relativeproportions of the materials used in the formation of the briquets maybe varied if desired, and I prefer that they be as low as practicable insilica and high in lime.

The briquets formed as described are then subjected under suitableconfinement (as in a furnace stack) to the reducing action of hotcarbonaceous gas at a temperature (preferably below 1400 F.)insufficient to smelt the ore or bind phosphorus to the iron. The fuel,from the combustion of which the hot reducing gases are generated, doesnot come into contact with the ore. After due subjection to the actionof the gases the iron con stituent of the ore, as it is changed to themetallic state, agglomerates into shells or skull of irregular form, andmay be characterized as sponge iron.

The temperature to which the ore is sub Specification of Letters Patent.

Application filed December 23, 1907.

Patented June 9, 1908.

Serial No. 407,773.

jected is insufiicient to flux the lime and silic ates which remain insolid form and in comminuted condition and will fall away where notcompletely enveloped by the iron. As in that state the lime has greataffinity for phosphorus, more or less of the latter is absorbed by andcarried away with the lime. Some of the phosphorus may be carried off bythe reducing gas.

It will be understood from the foregoing description that as the resultof my process the iron constituent of the ore is formed into what may becharacterized as sponge iron, either wholly dephosphorized or carryingbut little of the phosphorus as compared with the phosphor-content ofthe ore.

What I claim as new and desire to secure by Letters Patent, is

1. The method of treating finely divided iron ore to eliminate itsphosphor content, which consists in briqueting the ore with a mixturecontaining lime and subjecting the briqueted mixture to the action of areducing gas at a temperature sufficient to reduce the iron to ametallic state but insufficient to melt the ore or flux the lime, andcausing separation from the iron of the residual materials of saidmixture.

2. The herein described method of reducing and dephosphorizing finelydivided iron ore, which consists in forming the ore into cement briquetscontaining lime, and subj ecting the briquets to the action of areducing gas at a temperature suliicient to reduce and agglomerate theiron particles, but insufiicient to bind the phosphorus to the iron orflux the lime.

3. The herein described method of reducing and dephosphorizing finelydivided iron ore, which. consists in briqueting the ore with a bindingmixture of lime and clay and subjecting the briquets to the action of areducing gas at a temperature sufficient to reduce and agglomerate theiron particles but insufficient to bind the phosphorus to the iron orflux the lime.

JOHN T. JONES.

In presence of RALPH A. SOHAEFER, W. T. JoNEs.

